They went from a Flash app used live to an asynchronous web page model. I’ve got my account since that first app but only started using it when it got closer to what it is now (and got a camera phone).

People understand a website full of photos better than they understand an innovative chat interface with photo sharing. Power users got what we were doing with Flickr Live and learned to swim pretty quickly, but people like my mom weren’t quite as quick to figure it out… Also, there’s a huge advantage to the asynchronous nature of Web pages, where I can leave comments on a photo for someone to find at any later date. There’s a huge advantage to that over the synchronicity of the real-time chat, where if you’re not there to enjoy the conversation about a photo at any one specific time, you’ve missed it altogether.

Tags were not in the initial version of Flickr. Stewart Butterfield wanted to add them. He liked the way they worked on del.icio.us, the social bookmarking application. We added very simple tagging functionality, so you could tag your photos, and then look at all your photos with a particular tag, or any one person’s photos with a particular tag… Soon thereafter, users started telling us that what was really interesting about tagging was not just how you’ve tagged your photos, but how the whole Flickr community has been tagging photos. So we started seeing a lot of requests from users to be able to see a global view of the tagscape.

For most of the people I know Flickr is an accessory to our blog but for more and more users, it’s an end in itself, there are probably a lot who don’t even know what a blog is.

And people certainly use it in different ways. I primarily use it to share photos with my friends and family, and most of my photos are restricted so that only people I’ve said are my friends and family can view them. But we found that it took off when we got some excellent photographers who were interested in using Flickr as a new kind of photo blog, so that the world could see their pictures. And that, I think, is really the primary usage of Flickr now.

Rapid development cycle. And “as it comes” building instead of intensive spec. writing.

We deploy code to the site maybe 10 times a day on a busy day. And we’re constantly adding new features, small and large, even though lately it’s been relatively small features, sadly. (emphasis mine)

No, we’re not very formal! That can be kind of frustrating for me as an engineer who has to make the UI work. But it’s also what I thrive on, which is solving UI problems. So although we rarely have everything spec-ed out adequately, it’s part of the fun of doing the development, meeting challenges that arise as we start to actually build the UIs we’ve talked about.

Finally, since tags have been getting popular Karl has been saying that they aren’t that great for classification and will become unusable as the user bas grows. We’re starting to see this coming true in parts so I’m looking forward to what they come up with here:

We’re going to be releasing some really cool features pretty soon. We’re working on new features to increase the relevancy of tag search results. It’s quite exciting because there are a lot of fantastic photos on Flickr that people don’t always find. I think it’s going to change the nature of Flickr a little bit. It’s pretty cool.